1. Field of the Invention
The present invention relates to a control circuit and control method for comparator-controlled type DC-DC converters and, more particularly, to a switching control method of the main switching transistors and a control method of operating frequencies.
2. Description of the Related Art
There is a comparator-controlled PFM type DC-DC converter, in which, as a control system capable of making a high-speed response to a rapid change in the level of load, the output voltage of the DC-DC converter is compared with a reference voltage to thereby make on/off control of the main switching transistors.
Incidentally, as the above-described related art, there are disclosed Japanese unexamined patent publication No. 2005-518775 and Japanese unexamined patent publication No. 2005-12868.